LabVIEW
acquire images with labview via firewire and TWAIN
Just saw this and want to clarify on this. This is a total no-go! The Twain interface is a very old technology from the days when Windows was a cooperative multitasking environment without real tasks or threads. In order for Twain to allow for some sort of multitasked integration into an application it requires you to integrate the Twain handling into the message loop of your application. As you do not have direct control over the source code LabVIEW is written from, this is a very tedious operation, with Windows message hooks and such, lots and lots of semaphore protection to avoid race conditions etc. etc.
@AESulzer wrote:Michael,
From a more general standpoint, what you'll need to do is use a Call Library Function Node (located in the All Functions>>Advanced palette) to call the necessary functions out of those DLLs. Before you can do this, you'll need to know some specifics about what functions are available in those DLLs and what parameters/outputs are associated with them. This information is typically available in the product manual or perhaps someone else with experience with your specific device can speak to that. Once you know the functions necessary to execute the desired operations, you simply configure a Call Library Function Node for each of them and place them in your LabVIEW code.
There is simply no way that you can do anything even remotely workable just by using the Call Library Node. You will need a (rather complex) external shared library that goes in between Twain and LabVIEW and takes care of all the subtleties. I know for sure because I wrote such a beast in the past.
Now there is a Toolkit from the French Alliance member Alliance Vision http://www.alliancevision.com/us/index.html that does this. If you need Twain I would definitely go for this. My own library is only to the point of what I had needed for a particular project, (meaning it supports two specific scanners without issues) and without any documentation for external users and I couldn't give it away for free either.
Just want to warn you but there is a good chance that the Alliance Vision Twain Toolkit does not really give you full programmatic control of all the parameters of non-scanner devices and you won't be able to avoid letting the Twain driver show the device specific configuration dialog to manipulate specific settings.
In my own library I have low level functions to directly manipulate Twain attributes but in order to be able to use that you would need a through knowledge of the Twain specifications down to the API. That together with the difficulties to support other devices I don't have available, made us decide to not try to sell this Toolkit yet.
Rolf Kalbermatter
